On Instruments for Engagement

A commissioned essay for the catalogue that accompanied the Archizines exhibition first held at the Architectural Association, London. Informed by a variety of primary and secondary research sources, this essay intended to highlight and critically analyse the work of a range of practitioners who have deliberately removed themselves from mainstream media outlets and are concerned with using photography as a visual language to critique and focus attention on the spaces that we occupy and contribute to the wider debate regarding architecture and the built environment

The Poetic Archive: Photography, Everyday Life and the Tactic of Self-Publishing

Preston is my Paris was co-founded by Adam Murray and Robert Parkinson in June 2009. The project originally began as a photocopied zine specifically focussing on the city of Preston but has since developed into a multi-faceted photographic archive consisting of 40 self-published works that address themes relating to everyday life and social consciousness. In contrast to other photographic investigations of everyday life which often result in gallery exhibitions or lavishly produced books, Murray and Parkinson intentionally appropriate vernacular methods of production and print materials such as photocopying and newsprint with the aim to produce an archive that deliberately intends to engage with an audience beyond the conventional art world. This paper discusses this body of work and the role that the tactic of self-publishing has in a contemporary photographic context

Feature Map Filtering: Improving Visual Place Recognition with Convolutional Calibration

Convolutional Neural Networks (CNNs) have recently been shown to excel at performing visual place recognition under changing appearance and viewpoint. Previously, place recognition has been improved by intelligently selecting relevant spatial keypoints within a convolutional layer and also by selecting the optimal layer to use. Rather than extracting features out of a particular layer, or a particular set of spatial keypoints within a layer, we propose the extraction of features using a subset of the channel dimensionality within a layer. Each feature map learns to encode a different set of weights that activate for different visual features within the set of training images. We propose a method of calibrating a CNN-based visual place recognition system, which selects the subset of feature maps that best encodes the visual features that are consistent between two different appearances of the same location. Using just 50 calibration images, all collected at the beginning of the current environment, we demonstrate a significant and consistent recognition improvement across multiple layers for two different neural networks. We evaluate our proposal on three datasets with different types of appearance changes - afternoon to morning, winter to summer and night to day. Additionally, the dimensionality reduction approach improves the computational processing speed of the recognition system.Comment: Accepted to the Australasian Conference on Robotics and Automation 201

Three-dimensional coating and rimming flow : a ring of fluid on a rotating horizontal cylinder

The steady three-dimensional flow of a thin, slowly varying ring of Newtonian fluid on either the outside or the inside of a uniformly rotating large horizontal cylinder is investigated. Specifically, we study “full-ring” solutions, corresponding to a ring of continuous, finite and non-zero thickness that extends all the way around the cylinder. In particular, it is found that there is a critical solution corresponding to either a critical load above which no full-ring solution exists (if the rotation speed is prescribed) or a critical rotation speed below which no full-ring solution exists (if the load is prescribed). We describe the behaviour of the critical solution and, in particular, show that the critical flux, the critical load, the critical semi-width and the critical ring profile are all increasing functions of the rotation speed. In the limit of small rotation speed, the critical flux is small and the critical ring is narrow and thin, leading to a small critical load. In the limit of large rotation speed, the critical flux is large and the critical ring is wide on the upper half of the cylinder and thick on the lower half of the cylinder, leading to a large critical load. We also describe the behaviour of the non-critical full-ring solution, and, in particular, show that the semi-width and the ring profile are increasing functions of the load but, in general, non-monotonic functions of the rotation speed. In the limit of large rotation speed, the ring approaches a limiting non-uniform shape, whereas in the limit of small load, the ring is narrow and thin with a uniform parabolic profile. Finally, we show that, while for most values of the rotation speed and the load the azimuthal velocity is in the same direction as the rotation of the cylinder, there is a region of parameter space close to the critical solution for sufficiently small rotation speed in which backflow occurs in a small region on the upward-moving side of the cylinder

Measurement of performance using acceleration control and pulse control in simulated spacecraft docking operations

Nine commercial airline pilots served as test subjects in a study to compare acceleration control with pulse control in simulated spacecraft maneuvers. Simulated remote dockings of an orbital maneuvering vehicle (OMV) to a space station were initiated from 50, 100, and 150 meters along the station's -V-bar (minus velocity vector). All unsuccessful missions were reflown. Five way mixed analysis of variance (ANOVA) with one between factor, first mode, and four within factors (mode, bloch, range, and trial) were performed on the data. Recorded performance measures included mission duration and fuel consumption along each of the three coordinate axes. Mission duration was lower with pulse mode, while delta V (fuel consumption) was lower with acceleration mode. Subjects used more fuel to travel faster with pulse mode than with acceleration mode. Mission duration, delta V, X delta V, Y delta V., and Z delta V all increased with range. Subjects commanded the OMV to 'fly' at faster rates from further distances. These higher average velocities were paid for with increased fuel consumption. Asymmetrical transfer was found in that the mode transitions could not be predicted solely from the mission duration main effect. More testing is advised to understand the manual control aspects of spaceflight maneuvers better

Monetary Policy Rules For Manging Aid Surges In Africa

We examine the properties of alternative monetary policy rules in response to large aid surges in low-income countries characterized by incomplete capital market integration and currency substitution. Using a dynamic stochastic general equilibrium model, we show that simple monetary rules that stabilize the path of expected future seigniorage for a given aid flow have attractive properties relative to a range of conventional alternatives including those involving heavy reliance on bond sterilization or a commitment to a pure exchange rate float. These simple rules, which are shown to be robust across a range of fiscal responses to aid inflows, appear to be consistent with actual responses to recent aid surges in a range of post-stabilization countries in Sub-Saharan Africa.Basle Committee, capital adequacy, financial governance, financial architecture, financial reform, international standards, capital flows, poor countries, cost of capital, international development

Manual Control Aspects of Orbital Flight

A brief description of several laboratories' current research in the general area of manual control of orbital flight is presented. With an operational-space-station era (and its increased traffic levels) approaching, now is an opportune time to investigate issues such as docking and rendezvous profiles and course-planning aids. The tremendous increase in the capabilities of computers and computer graphics has made extensive study possible and economical. It is time to study these areas, from a human factors and manual control perspective in order to preclude the occurrence of problems analogous to those that occurred in the airline and other related industries

Aid versus trade revisited

This paper examines the (non) equivalance between aid flows and trade preferences as alternative forms of donor assistance in the presence of learning-by-doing externalities in recipient country export production. Using a two-period model based on vanWijnbergen (1985), in which the productivity externality consistitues the only (inter-temporal) distortion, we show that switching donor support on the margin from aid to trade preferences can increase recipient country welfare. To evaluate the size of this potential welfare gain to small African economies we simulate donor policy reforms using a dynamic CGE model where the productivity externality may also interact with private capital accumulation. We show that for reasonable values of key behavioural parameters, the potential growth and welfare gains from a (donor) revenue neutral re-orientation of assistance to developing countries could be substantial. The paper concludes by considering why these potential dynamic gains appear to be unexpoited by both donors and recipients.Foreign Aid, Trade Preferences, Africa.

Aid and Fiscal Instability

We show that a combination of temporariness and spending pressure is intrinsic to the aid relationship. In our analysis, recipients rationally discount the pronouncements of donors about the duration of their commitments because in equilibrium they know that some donors will honor those commitments while others will not. Donor types pool in equilibrium; in sharp contrast to conventional signaling situations, there is no separating equilibrium in pure strategies. Moreover, pooling necessarily creates what we call ex ante fiscal instability: expenditure smoothing is perfect ex post if the donor proves permanent, but if the donor is temporary the recipient faces an aid collapse and a fiscal adjustment problem. The Samaritan’s dilemma is at work here, in the guise of a use-it-or-lose-it restriction on spending out of aid. This restriction can produce ex ante fiscal instability even when information is symmetric.Aid, Fiscal instability, Use it or lose it, Samaritan’s dilemma, Pooling

Aid volatility, monetary policy rules and the capital account in African economies

We examine the properties of simple quantity-based monetary policy rules of the kind widely used in low-income African economies. Using a DSGE model and focusing our attention on responses to positive aid shocks, we suggest that policy rules involving substantial reserve accumulation in the face of aid surges serve to ease macroeconomic adjustment to shocks, particularly when a portion of aid is used to support fiscal adjustment. These rules are robust to assumptions about the degree of integration of the domestic public debt market with world capital markets. Although an open capital account facilitates smoother adjustment to temporary aid surges when an aid inflow is fully spent, it exacerbates the adjustment problem when aid is accompanied by fiscal adjustment and hence reinforces the case for a managed float in such circumstances.Monetary policy, Africa, Aid volatility, foreign capital flows, stochastic simulation models